Gas generating composition for inflator containing melamine cyanurate

ABSTRACT

To provide a gas generating composition for air bag which is low in toxicity, large in burning rate, and low in combustion temperature. Gas generating compositions comprising (a) melamine cyanurate or a mixture of melamine cyanurate and nitrogen-containing organic compound and (b) oxygen-containing oxidant, and gas generating compositions comprising (c) binder and (d) additive are provided.

This application is a Divisional of co-pending application Ser. No.10/633,645, filed on Aug. 5, 2003, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120. Ser. No. 10/633,645 application claims priority under 35U.S.C. §119(e) on U.S. Provisional Application No. 60/401,761 filed onAug. 8, 2002 and under 35 U.S.C. §119(a) on Patent Application No.2002-227094 filed in Japan on Aug. 5, 2002, which are hereinincorporated by reference.

TECHNICAL FIELD TO WHICH THE INVENTION BELONGS

The present invention relates to a gas generating composition which issuitable for air bag restraining system in automobiles and the like, itsmolded article and an air bag inflator using the same.

PRIOR ART

Conventionally, compositions using sodium azide have been often used asa gas generating agent for an air bag which serves as an occupantprotecting apparatus in an automobile. However, as the toxicity to humanbody [LD50 (oral-tat)=27 mg/kg] and danger in handling of sodium azideis becoming problems, gas generating compositions containing variouskinds of nitrogen-containing organic compounds have been developed asso-called non-azide based gas generating compositions which are saferalternatives.

U.S. Pat. No. 4,909,549 discloses a composition comprising ahydrogen-containing tetrazole, a triazole compound and anoxygen-containing oxidant. U.S. Pat. No. 4,370,181 discloses a gasgenerating composition comprising a metal salt of bitetrazole notcontaining hydrogen and an oxidant not containing oxygen. U.S. Pat. No.4,369,079 discloses a gas generating composition comprising a metal saltof bitetrazole not containing hydrogen, alkaline metal nitrate, alkalinemetal nitrite, alkaline earth metal nitrate, alkaline earth metalnitrite and a mixture thereof. U.S. Pat. No. 5,542,999 discloses a gasgenerating agent comprising a fuel such as GZT, TAGN(triaminonitroguanidine), NG (nitroguanidine), NTO and the like, basiccopper nitrate, a catalyst which reduces toxic gas and a coolant agent.JP-A No. 10-72273 discloses a gas generating agent comprising abitetrazole metal salt, a bitetrazole ammonium salt, aminotetrazole andammonium nitrate. JP-A No. 2001-220282 discloses a gas generating agentcomprising a triazine derivative and a basic metal nitrate.

The above non-azide based gas generating compositions, however, haveproblems in respect of combustion temperature, burning rate, phasetransition, amounts of generated carbon monoxide and nitrogen oxide, gasoutput, safety in handling and the like.

The gas generating composition disclosed in U.S. Pat. No. 4,369,079 hasa high combustion temperature, and hence require a large amount ofcoolant in practical use. The composition of U.S. Pat. No. 5,542,999 hasa small burning rate, and therefore, there is a possibility such that itis not burnt completely in a short period of time. As to the gasgenerating agent in JP-ANo. 10-72273, a molded article of a gasgenerating composition is broken due to a form change caused by phasetransition of ammonium nitrate in the use temperature range, so thatstable combustion cannot be obtained. In the patents of non-azide basedgas generating agents other than JP-A No. 2001-220282, tetrazoles,nitroguanidine, TAGN and the like are used as a fuel for gas generatingagent, but they are dangerous substances and has to be handled withspecial attention.

In addition, there is no prior art, including the invention disclosed inJP-A No. 2001-220282, that uses melamine cyanurate as a fuel of a gasgenerating agent.

DISCLOSURE OF THE INVENTION

Accordingly, an object of the present invention is to provide a gasgenerating composition having a low combustion temperature, generatingonly small amounts of carbon monoxide and nitrogen oxide and being safein handling, and a molded article thereof, as well as an inflator forair bag using the same.

The present invention provides a gas generating composition comprisingComponent (a) as described below, and Component (b) if required:

(a) melamine cyanurate or a mixture of melamine cyanurate andnitrogen-containing organic compound serving as a fuel;

(b) oxygen-containing oxidant.

In the above aspect of the invention, although the gas generatingcomposition may comprise Component (a) but not Component (b), the gasgenerating composition preferably comprises both Component (a) andComponent (b).

Furthermore, the present invention provides a molded article in a shapeof a single-perforated cylinder, a perforated (porous) cylinder or apellet obtained from the above gas generating composition. The singlepore or multi pores may be a through hole or a non-through hole.

Furthermore, the present invention provides an inflator for air bagusing the above gas generating composition and the molded article.

Since the gas generating composition and its molded article according tothe present invention are low in toxicity and less dangerous, so thatthey are safe in handling, and have a large burning rate, a lowcombustion temperature and small amounts of generated carbon monoxideand nitrogen oxide at the time of combustion.

PREFERRED EMBODIMENT OF THE INVENTION

Melamine cyanurate or a mixture of melamine cyanurate andnitrogen-containing organic compound of Component (a) used in thepresent invention is low in toxicity, and is preferably combined withComponent (b) because low combustion temperature and large burning ratecan be obtained.

Melamine cyanurate is desirable because it has such low toxicity of LD50(oral-rat)=2020 mg/kg and excellent thermal stability, and is safe inhandling and inexpensive.

An example of the nitrogen-containing organic compound can be one or atleast two selected from the group consisting of tetrazole compoundsincluding 5-aminotetrazole and bitetrazole ammonium salt; guanidinecompounds including nitroguanidine, guanidine nitrate anddicyanediamide; and triazine compounds including melamine, trimethylolmelamine, alkylated methylol melamine, ammeline, ammelande, nitrate saltof melamine, perchlorate salt of melamine, trihydrazino triazine andnitrated compound of melamine.

In view of solving the problem of the invention, the blending ratio(mass ratio) of nitrogen-containing organic compound/melamine cyanuratein preparing a mixture of melamine cyanurate and a nitrogen-containingorganic compound is preferably 0.05 to 8, more preferably 0.1 to 6, andstill more preferably 0.2 to 2.

An example of the oxygen-containing oxidant of Component (b) used in thepresent invention can be one or at least two selected from the groupconsisting of metal nitrates, ammonium nitrate, metal perchlorates,ammonium perchlorate, metal nitrites, metal chlorates, basic coppernitrate, basic cobalt nitrate, basic zinc nitrate and basic manganesenitrate, and among these, basic copper nitrate is preferable.

The basic copper nitrate has excellent thermal stability because phasetransition does not occur in the use temperature range and it has a highmelting point. In addition, since it acts to lower the combustiontemperature of gas generating agent, an amount of generated nitrogenoxide can also be reduced.

In case of making the gas generating composition of the presentinvention two-component system consisting of Component (a) and Component(b), the content of Component (a) is preferably 10 to 60% by mass, andmore preferably 15 to 50% by mass. The content of Component (b) ispreferably 40 to 90% by mass, and more preferably from 50 to 85% bymass.

One preferred embodiment of the gas generating composition oftwo-component system comprises (a) melamine cyanurate and (b) basiccopper nitrate. In this case, the content of (a) melamine cyanurate ispreferably 15 to 40% by mass and the content of (b) basic copper nitrateis preferably 60 to 85% by mass.

Another preferred embodiment of the gas generating composition oftwo-component system comprises (a) a mixture of melamine cyanurate andguanidine nitrate and (b) basic copper nitrate. In this case, thecontent of (a) a mixture of melamine cyanurate and guanidine nitrate ispreferably 15 to 60% by mass and the content of (b) basic copper nitratepreferably is 40 to 85% by mass.

Another preferred embodiment of the gas generating composition oftwo-component system comprises (a) a mixture of melamine cyanurate andmelamine and (b) basic copper nitrate. In this case, the content of (a)a mixture of melamine cyanurate and melamine is preferably 15 to 50% bymass and the content of (b) basic copper nitrate is preferably from 50to 85% by mass.

Another preferred embodiment of the gas generating composition oftwo-component system comprises (a) a mixture of melamine cyanurate andbitetrazole ammonium salt and (b) basic copper nitrate. In this case,the content of (a) a mixture of melamine cyanurate and bitetrazoleammonium salt is preferably 15 to 50% by mass and the content of (b)basic copper nitrate is preferably 50 to 85% by mass.

When the gas generating composition of the present invention is preparedby one-component system of Component (a), two-component system ofComponents (a) and (b), or three-component system of Components (a), (b)and (d), if the molding strength of the molded article is notsufficient, there may be a possibility such that the molded articlecollapses and burns too violently to control the combustion in actualcombustion. For this reason, a binder of Component (c) is preferablyadded.

The binder of Component (c) can be one or at least two selected from thegroup consisting of carboxymethyl cellulose (CMC), sodium carboxymethylcellulose (CMCNa), potassium carboxymethyl cellulose, ammoniumcarboxymethyl cellulose, cellulose acetate, cellulose acetate butylate(CAB), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethylcellulose (HEC), ethylhydroxyethyl cellulose (EHEC), hydroxypropylcellulose (HPC), carboxymethylethyl cellulose (CMEC), microcrystalcellulose, polyacrylamide, amino compound of polyacrylamide,polyacrylhydrazide, acrylamide/acrylic acid metal salt copolymer,polyacrylamide/polyacrylic acid ester compound copolymer, polyvinylalcohol, acrylic rubber, guar gum, starch and silicone. Among these,sodium carboxymethyl cellulose (CMCNa) and guar gum are preferable inview of the adherence of the binder, cost, ignitionability and the like.

When the gas generating composition of the present invention is preparedby a one-component system of Component (a), two-component system ofComponents (a) and (b), or three-component system of Components (a), (b)and (c), it is preferable to further add an additive of Component (d) inorder to adjust the burning rate of gas generating agent and clean thecombustion gas.

The additive of Component (d) can be at least one selected from thegroup consisting of metal oxides such as copper (II) oxide, iron oxide,zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickeloxide, bismuth oxide, silica, alumina; metal hydroxides such as aluminumhydroxide, magnesiumhydroxide, cobalt hydroxide, iron hydroxide; metalcarbonates or basic metal carbonates such as cobalt carbonate, calciumcarbonate, basic zinc carbonate, basic copper carbonate; complexcompounds of metal oxides or hydroxides such as Japanese acid clay,kaolin, talc, bentonite, diatomaceous earth, hydrotalcite; metal acidsalts such as sodium silicate, mica molybdate, cobalt molybdate,ammonium molybdate; silicone, molybdenum disulfide, calcium stearate,siliconnitride, siliconcarbide, metaboric acid, boric acid and boricanhydride.

For reducing an amount of generated carbon monoxide after combustion ofthe gas generating composition, it is preferred to add aluminumhydroxide or cobalt oxide as Component (d). When the gas generatingcomposition of the present invention is prepared by three-componentsystem or four-component system of Components (a) to (d), the contentsof the respective components are as follows: the content of Component(a) is preferably 10 to 60% by mass and more preferably 10 to 50% bymass; the content of Component (b) is preferably 40 to 90% by mass, andmore preferably 50 to 80% by mass; the content of Component (c) ispreferably 0 to 15% by mass, and more preferably 1 to 10% by mass; andthe content of Component (d) is preferably not more than 20% by mass,and more preferably 0.5 to 15% by mass.

One preferred embodiment of the gas generating composition ofthree-component system comprises melamine cyanurate of Component (a) andbasic copper nitrate of Component (b) and sodium carboxymethyl celluloseor guar gum of Component (c). In this case, the content of melaminecyanurate of Component (a) is preferably 15 to 30% by mass, basic coppernitrate of Component (b) is preferably 40 to 90% by mass and sodiumcarboxymethyl cellulose or guar gum of Component (c) is preferably 0.1to 10% by mass.

Another preferred embodiment of the gas generating composition ofthree-component system comprises a mixture of melamine cyanurate andguanidine nitrate of Component (a) and basic copper nitrate of Component(b) and sodium carboxymethyl cellulose or guar gum of Component (c). Inthis case, the content of a mixture of melamine cyanurate and guanidinenitrate of Component (a) is preferably 15 to 50% by mass, basic coppernitrate of Component (b) is preferably 50 to 80% by mass and sodiumcarboxymethyl cellulose or guar gum of Component (c) is preferably 0.1to 10% by mass.

Another preferred embodiment for the gas generating composition ofthree-component system comprises a mixture of melamine cyanurate andmelamine of Component (a) and basic copper nitrate of Component (b) andsodium carboxymethyl cellulose or guar gum of Component (c). In thiscase, the content of a mixture of melamine cyanurate and melamine ofComponent (a) is preferably 15 to 30% by mass, basic copper nitrate ofComponent (b) is preferably 60 to 80% by mass and sodium carboxymethylcellulose or guar gum of Component (c) is preferably 0.1 to 10% by mass.

One preferred embodiment of the gas generating composition offour-component system comprises melamine cyanurate of Component (a),basic copper nitrate of Component (b), sodium carboxymethyl cellulose ofComponent (c) and aluminum hydroxide of Component (d). In this case, thecontent of melamine of Component (a) is preferably 10 to 30% by mass,basic copper nitrate of Component (b) is preferably 40 to 90% by mass,sodium carboxymethyl cellulose of Component (c) is preferably 0.1 to 10%by mass, and aluminum hydroxide of Component (d) is preferably 0.5 to15% by mass.

Another preferred embodiment for the gas generating composition offour-component system comprises a mixture of melamine cyanurate andguanidine nitrate of Component (a), basic copper nitrate of Component(b), sodium carboxymethyl cellulose of Component (c) and aluminumhydroxide of Component (d). In this case, the content of a mixture ofmelamine cyanurate and guanidine nitrate of Component (a) is preferably10 to 50% by mass, basic copper nitrate of Component (b) is preferably40 to 90% by mass, sodium carboxymethyl cellulose of Component (c) ispreferably 0.1 to 10% by mass, and aluminum hydroxide of Component (d)is preferably 1 to 10% by mass.

Another preferred embodiment for the gas generating composition offour-component system comprises a mixture of melamine cyanurate andmelamine of Component (a), basic copper nitrate of Component (b), sodiumcarboxymethyl cellulose of Component (c) and aluminum hydroxide ofComponent (d). In this case, the content of a mixture of melaminecyanurate and melamine of Component (a) is preferably 10 to 30% by mass,basic copper nitrate of Component (b) is preferably 40 to 90% by mass,sodium carboxymethyl cellulose of Component (c) is preferably 0.1 to 10%by mass, and aluminum hydroxide of Component (d) is preferably 0.1 to15% by mass.

Another preferred embodiment for the gas generating composition offour-component system comprises melamine cyanurate of Component (a),basic copper nitrate of Component (b), sodium carboxymethyl cellulose ofComponent (c) and magnesium hydroxide or metaboric acid of Component(d). In this case, the content of melamine cyanurate of Component (a) ispreferably 10 to 30% by mass, basic copper nitrate of Component (b) ispreferably 40 to 90% by mass, sodium carboxymethyl cellulose ofComponent (c) is preferably 0.1 to 10% by mass, and magnesium hydroxideor metaboric acid of Component (d) is preferably 1 to 10% by mass.

Another preferred embodiment for the gas generating composition offour-component system comprises melamine cyanurate of Component (a),basic copper nitrate of Component (b), sodium carboxymethyl cellulose ofComponent (c) and one or at least two additives selected from the groupconsisting of aluminum oxide, silica, Japanese acid clay anddiatomaceous earth of Component (d). In this case, the content ofmelamine cyanurate of Component (a) is preferably 10 to 30% by mass,basic copper nitrate of Component (b) is preferably 50 to 80% by mass,sodium carboxymethyl cellulose of Component (c) is preferably 0.1 to 10%by mass, and the additive of Component (d) is preferably 0.1 to 10% bymass.

The gas generating composition of the present invention can be moldedinto a desired shape such as a single-perforated cylinder, a perforated(porous) cylinder or a pellet. These molded articles can be produced byadding and mixing water or an organic solvent into the gas generatingcomposition, and then extrusion-molding this (in case of asingle-perforated cylinder or a perforated (porous) cylinder) orcompression-molding this with pelletizer (in case of a pellet).

The gas generating composition according to the present invention or themolded article obtained therefrom can be applied in various kinds ofvehicles to an inflator for an air bag for a driver side, inflator foran air bag for passenger side, inflator for an air bag for sidecollision, inflator for a inflatable curtain, inflator for a kneebolster, inflator for inflatable a seat belt, inflator for a tubularsystem and a gas generator for a pretensioner.

Furthermore, inflators using the gas generating composition of thepresent invention or the molded article obtained therefrom may be eitherpyrotechnic type in which gas is supplied only from a gas generatingagent or hybrid type in which gas is supplied from both compressed gassuch as argon and gas generating agent.

Furthermore, the gas generating composition of the present invention orthe molded article obtained therefrom can also be used as an ignitingagent called as an enhancer agent (or booster) for transmitting energyof a detonator or squib to a gas generating agent.

EXAMPLES

In the followings, the present invention will be described in detail byway of Examples, however, the present invention is not limited to theseExamples.

Examples 1 to 18, Comparative Examples 1 and 2

Gas generating compositions having compositions shown in Table 1 wereproduced. Combustion temperature, gas output (the unit mol/100 grepresents the number of moles of generated gas per 100 g ofcomposition), and amounts of generated CO and NO of these compositionsdetermined by theoretical calculation are shown in Table 1.

TABLE 1 Combustion Generated Generated temperature Gas output amount ofCO amount of NO Composition (composition ratio: % by mass) (k) (mol/100g) (mol/100 g) (mol/100 g) Example 1 MC/BCN (26.16/73.84) 1348 2.15 1.31× 10⁻⁴  0 Example 2 MC/BCN/CMCNa (23.09/73.91/3) 1358 2.14 1.4 × 10⁻² 0Example 3 MC/BCN/CMCNa/Al(OH)₃ (22.31/71.69/3/3) 1294 2.14 1.3 × 10⁻² 0Example 4 MC/BCN/CMCNa/Al(OH)₃ (21.79/70.21/3/5) 1251 2.13 1.2 × 10⁻² 0Example 5 MC/BCN/CMCNa/Al(OH)₃ (17.24/70.76/7/5) 1298 2.09 1.3 × 10⁻² 0Example 6 MC/GN/BCN (21.29/10/68.71) 1390 2.32 1.3 × 10⁻³ 0 Example 7MC/GN/BCN (16.39/20/63.61) 1493 2.48 1.32 × 10⁻³  0 Example 8 MC/GN/BCN(6.59/40/53.41) 1674 2.80 1.50 × 10⁻²  2.76 × 10⁻⁵  Example 9MC/Melamine/BCN (24.93/1/74.07) 1357 2.15 1.05 × 10⁻³  0 Example 10MC/GN/BCN/CMCNa (18.37/5/71.63/5) 1379 2.20 1.4 × 10⁻² 0 Example 11MC/GN/BCN/CMCNa (15.92/10/69.08/5) 1432 2.28 1.4 × 10⁻² 0 Example 12MC/GN/BCN/CMCNa (11.02/20/63.98/5) 1532 2.44 1.4 × 10⁻² 0 Example 13MC/Melamine/BCN/CMCNa (17.05/3/74.95/5) 1358 2.11 1.4 × 10⁻² 0 Example14 MC/GN/BCN/CMCNa/Al(OH)₃ 1358 2.27 1.3 × 10⁻² 0 (14.61/10/65.39/5/5)Example 15 MC/GN/BCN/CMCNa/Al(OH)₃ (9.71/20/60.29/5/5) 1429 2.43 1.3 ×10⁻² Example 16 MC/Melamine/BCN/CMCNa/Al(OH)₃ 1307 2.11 1.3 × 10⁻²(15.74/3/71.26/5/5) Example 17 MC/GN/BCN/Al(OH)₃ (20.3/10/64.7/5) 13252.32 1.2 × 10⁻² Example 18 MC/GN/BCN/Al(OH)₃ (15.4/20/59.6/5) 1376 2.481.2 × 10⁻² Comparative BHTK/KNO₃ (51.44/48.56) 2393 1.26 5.1 × 10⁻⁴ 4.1× 10⁻³ example 1 Comparative NaN₃/CuO (61/39) 1421 1.41 0 1.3 × 10⁻⁶example 2

In Table 1, “MC” denotes melamine cyanurate, “GN” guanidine nitrate,“BCN” basic copper nitrate, “CMCNa” sodium carboxymethyl cellulose and“BHTK” potassium bitetrazole. The same denotations are used in othertables.

Combustion temperatures of Examples 1 to 18 were lower than that ofComparative example 1 of non-azide based gas generating agent. As toExamples 1 to 14, a theoretical amount of generated NO was zero, showingthat they were more effective in reducing an amount of generated NO thanComparative Examples 1 and 2. In Examples 1 to 18, gas output isimproved by 40% or more compared with Comparative Example 2 of azidebased gas generating agent.

Examples 19 to 24

Gas generating compositions having compositions shown in Table 2 wereproduced. Friction sensitivity and drop hammer sensitivity of thesecompositions were tested according to the explosives performance testmethod of JIS K4810-1979. The results are shown in Table 2.

TABLE 2 Drop Friction hummer Composition sensitivity sensitivity(composition ratio: % by mass) (N) (cm) Examples 19MC/BCN/(26.16/73.84) >353 >100 Examples 20 MC/BCN/CMCNa(23.09/73.91/3) >353 >100 Examples 21 MC/BCN/CMCNa/Al(OH)₃ >353 >100(22.31/71.69/3/3) Examples 22 MC/GN/BCN/Al(OH)₃ >353 60-70(20.3/10/64.7/5) Examples 23 MC/GN/BCN/CMCNa/Al(OH)₃ >353 60-70(9.71/20/60.29/5/5) Examples 24 MC/Melamine/BCN/CMCNa >353 >100(17.05/3/74.95/5)

In Examples 19 to 24, friction sensitivities exceeded 353 N and drophammer sensitivities are more than 60 cm, suggesting that friction anddrop hammer sensitivities are insensitive, and hence safety in handlingis high.

Examples 25 to 27

Gas generating compositions having compositions shown in Table 3 wereproduced. For these gas compositions, melting temperature, exothermicdecomposition starting temperature and TG weight reduction startingtemperature were measured using a TAS-type differential thermal analyzer(produced by Rigaku Corporation). The temperature raising speed duringmeasurement was 20° C./min, the measurement atmosphere was nitrogen gas,and the sample amount in measurement was 1 to 2 mg. The results areshown in Table 3.

TABLE 3 Exothermic Weight decomposition reduction Composition Meltingstarting starting (Composition ratio: % temperature temperaturetemperature by mass) (° C.) (° C.) (° C.) Example 25 MC (100) 280 — 284Example 26 MC/BCN (26.16/73.84) 220 250 226 Example 27 MC/BCN/CMCNa 210239 212 (23.09/73.91/3)

In Examples 25 to 27, melting temperature, exothermic decompositionstarting temperature and weight reduction starting temperature were 200°C. or more, suggesting excellent thermal stability.

Examples 28 to 29

Gas generating compositions having formulations shown in Table 4 wereproduced. These compositions were molded into a strand, and a burningrate was measured under nitrogen atmosphere at pressures of 4900, 6860,8820 kPa. The burning rate at 6860 kPa, and pressure index between 4900and 8820 kPa are shown in Table 4. Pressure index was determined fromthe following formula: rb=αPn (wherein, rb: burning rate, α:coefficient, P: pressure and n: pressure index).

TABLE 4 Composition (composition Burning rate Pressure ratio: % by mass)(mm/sec) index Example 28 MC/BCN/CMCNa 9.95 0.23 (23.09/73.91/3) Example29 MC/BCN/CMCNa/Al(OH)₃ 8.68 0.31 (22.31/71.69/3/3)

As is apparent from the above, each numerical value shown in Examples 28to 29 shows that practical requirement required for a gas generatingcomposition for inflator gas is satisfied.

1-30. (canceled)
 31. A gas generating composition, comprising: (a) amixture comprising melamine cyanurate and a nitrogen-containing organiccompound as fuel, and (b) an oxygen-containing oxidant, wherein thenitrogen-containing organic compound is selected from the groupconsisting of tetrazole compounds, guanidine compounds and triazinecompounds.
 32. The gas generating composition according to claim 31,wherein the tetrazole compounds are selected from the group consistingof 5-aminotetrazole and ammonium bitetrazole, the guanidine compoundsare selected from the group consisting of nitroguanidine, guanidinenitrate and dicyandiamide, and the triazine compounds are selected fromthe group consisting of melamine, trimethylol melamine, alkylatedmethylol melamine, ammeline, ammelande, nitrate salt of melamine,perchlorate salt of melamine, trihydrazino triazine and nitratedcompound of melamine.
 33. The gas generating composition according toclaim 31, wherein the content of Component (a) is 10 to 60% by mass, andthe content of Component (b) is 40 to 90% by mass.
 34. The gasgenerating composition according to claim 31, wherein theoxygen-containing oxidant of Component (b) is one or at least twoselected from the group consisting of metal nitrates, ammonium nitrate,metal perchlorates, ammonium perchlorate, metal nitrites, metalchlorates, basic copper nitrate, basic cobalt nitrate, basic zincnitrate and basic manganese nitrate.
 35. The gas generating compositionaccording to claim 31, wherein the oxygen-containing oxidant ofComponent (b) is one or at least two selected from the group consistingof basic copper nitrate, basic cobalt nitrate, basic zinc nitrate andbasic Manganese nitrate.
 36. The gas generating composition according toclaim 31, further comprising at least one component selected from (c)and (d): (c) binder; and (d) additive selected from metal oxides, metalhydroxides, metal carbonates, boric acid, and metaboric acid.
 37. Thegas generating composition according to claim 36, wherein the content ofComponent (a) is 10 to 60% by mass, the content of Component (b) is 40to 90% by mass, the content of Component (c) is 0 to 15% by mass, andthe content of Component (d) is 20% by mass or less.
 38. The gasgenerating composition according to claim 36 or 37, wherein Component(c) is at least one binder selected from the group consisting ofcarboxymethyl cellulose (CMC), sodium carboxymethyl cellulose, potassiumcarboxymethyl cellulose, ammonium carboxymethyl cellulose, celluloseacetate, cellulose acetate butylate, methyl cellulose, ethyl cellulose,hydroxyethyl cellulose, ethylhydroxyethyl cellulose, hydroxypropylcellulose, carboxymethylethyl cellulose, microcrystal cellulose,polyacrylamide, amino compound of polyacrylamide, polyacrylhydrazide,acrylamide/acrylic acid metal salt copolymer, polyacrylamide/polyacrylicacid ester compound copolymer, polyvinyl alcohol, acrylic rubber, guargum, starch and silicone.
 39. The gas generating composition accordingto claim 36 or 37, wherein Component (d) is at least one additiveselected from the group consisting of metal oxides including copperoxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenumoxide, nickel oxide, bismuth oxide, silica and alumina; metal hydroxidesincluding aluminum hydroxide, cobalt hydroxide, iron hydroxide andmagnesium hydroxide; metal carbonates or basic metal carbonatesincluding cobalt carbonate, calcium carbonate, basic zinc carbonate andbasic copper carbonate; complex compounds of metal oxides or hydroxidesincluding Japanese acid clay, kaolin, talc, bentonite, diatomaceousearth and hydrotalcite; metal acid salts including sodium silicate, micamolybdate, cobalt molybdate and ammonium molybdate; silicone, molybdenumdisulfide, calcium stearate, silicon nitride, silicon carbide, metaboricacid, boric acid and boric anhydride.
 40. The gas generating compositionaccording to claim 31, comprising melamine cyanurate as Component (a)and basic copper nitrate as Component (b).
 41. The gas generatingcomposition according to claim 31, comprising 15 to 40% by mass ofmelamine cyanurate as Component (a) and 60 to 85% by mass of basiccopper nitrate as Component (b).
 42. The gas generating compositionaccording to claim 31, comprising 15 to 60% by mass of a mixture ofmelamine cyanurate and guanidine nitrate as Component (a) and 40 to 85%by mass of basic copper nitrate as Component (b).
 43. The gas generatingcomposition according to claim 31, comprising 15 to 50% by mass of amixture of melamine cyanurate and melamine as Component (a) and 50 to85% by mass of basic copper nitrate as Component (b).
 44. The gasgenerating composition according to claim 31, comprising 15 to 50% bymass of a mixture of melamine cyanurate and ammonium bitetrazole asComponent (a) and 50 to 85% by mass of basic copper nitrate as Component(b).
 45. The gas generating composition according to claim 36,comprising 15 to 50% by mass of a mixture of melamine cyanurate andguanidine nitrate as Component (a), 50 to 80% by mass of basic coppernitrate as Component (b) and 0.1 to 10% by mass of sodium carboxymethylcellulose or guar gum as Component (c).
 46. The gas generatingcomposition according to claim 36, comprising 15 to 30% by mass of amixture of melamine cyanurate and melamine as Component (a), from 60 to80% by mass of basic copper nitrate as Component (b) and from 0.1 to 10%by mass of sodium carboxymethyl cellulose or guar gum as Component (c).47. The gas generating composition according to claim 36, comprising 10to 50% by mass of a mixture of melamine cyanurate and guanidine nitrateas Component (a), 40 to 90% by mass of basic copper nitrate as Component(b), 0.1 to 10% by mass of sodium carboxymethyl cellulose as Component(c), and 1 to 10% by mass of aluminum hydroxide as Component (d). 48.The gas generating composition according to claim 36, comprising 10 to30% by mass of a mixture of melamine cyanurate and melamine as Component(a), 40 to 90% by mass of basic copper nitrate as Component (b), 0.1 to10% by mass of sodium carboxymethyl cellulose as Component (c), and 0.1to 15% by mass of aluminum hydroxide as Component (d).
 49. A moldedarticle of a gas generating composition in a shape of asingle-perforated cylinder or perforated (porous) cylinder obtained byextrusion of the gas generating composition according to claim 31 or 36.50. A molded article of a gas generating composition in a shape ofpellet obtained by compression-molding the gas generating compositionaccording to claim 31 or
 36. 51. An inflator for an air bag using thegas generating composition according to claim 31 or
 36. 52. An inflatorfor an air bag using the molded article of the gas generating agentaccording to claim
 49. 53. An inflator for an air bag using the moldedarticle of the gas generating agent according to claim
 50. 54. The gasgenerating composition according to claim 31, wherein theoxygen-containing oxidant of component (b) is basic copper nitrate. 55.An air bag inflator comprising a gas generating composition comprising:(a) a mixture comprising melamine cyanurate and a nitrogen-containingorganic compound as fuel, and (b) an oxygen-containing oxidant, whereinthe nitrogen-containing organic compound is selected from the groupconsisting of tetrazole compounds, guanidine compounds and triazinecompounds.